The invention relates to a circuit arrangement for producing a low frequency alternating current, the frequency of which is to be adjustable within the range of about 0-100 Hz.
Circuit arrangements of this type are used in electric massaging devices.
In a known circuit arrangement, a low frequency alternating current is produced and the normal line frequency of 50 Hz is superimposed on said low frequency alternating current so that a time-dependent increase and decrease in the amplitude is attained. Voltage peaks, which in spite of the existing attenuation may pose a threat to the patient, may occur as a result of disturbances in the line voltage during gating through a transformer. An additional disadvantage of such a known circuit arrangement is seen in that the frequency of the amplitude which varies as a function of time and the oscillation curve or the shape of the oscillation curve are not controllable as desired.